<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>

    //构造函数
    function Boo(){
        function mf(obj){
            console.log(obj)
            obj.pp = 'ppp';
        }
        this.legs = 2;
        this.ff1 = function(){
//           this.legs = 10;
            mf(this);
        }
    }
    var b = new Boo();
</script>
</body>
</html>